In general, organic electronic devices are devices characterized in that a phenomenon such as light emission or a flow of electricity occurs when charges are injected into an organic layer provided between a positive electrode and a negative electrode, and it is possible to manufacture a device which serves various functions according to the organic material selected.
As a representative example, organic light emitting diodes (OLEDs) have drawn attention in the next-generation flat panel display field, the flexible display field, the lighting field, and the like because the OLEDS are thin and lightweight and have excellent color impression, and may be manufactured on a glass substrate, an inorganic material substrate comprising silicon, a metal substrate, and a flexible substrate such as a plastic substrate or a metal foil in the related art. These organic electronic devices are extremely vulnerable to moisture and oxygen and thus have a disadvantage in that light emitting efficiency and a service life are significantly reduced when the devices are exposed to the air or when moisture is introduced into the inside of a panel from the outside.
The encapsulation technology is an essential process for preventing oxidation of a light emitting material and an electrode material by blocking moisture and oxygen introduced from the outside of an OLED, and furthermore, for protecting the device from mechanical and physical impacts applied from the outside of the device.
In order to solve the aforementioned problem, attempts have been made to block moisture and oxygen introduced from the outside by using an encapsulant film using a glass cap or a metal cap or a laminating method or depositing inorganic materials.
However, the glass cap has disadvantages in that costs caused by glass processing are increased due to implementing a large area of a panel, and there is a problem with implementing a large area thereof due to mechanical damage, and the like, and also has difficulties in manufacturing a flexible OLED panel which requires flexibility. The metal cap has a problem with a process caused by a difference in thermal expansion coefficient between the metal cap and a substrate. Further, a bonding film using the laminating method has a problem in that moisture and oxygen are introduced through an interface with a bonding surface of the film.
Furthermore, when using a metal cap method in which a moisture absorbent is provided inside a panel during the encapsulation of the organic electronic device, an extension portion which protrudes at a predetermined height is formed in a metal cap structure for using a moisture absorbent, and when the metal cap is lastly bonded to a substrate using a bonding agent, or an organic light emitting diode is encapsulated by processing glass to form a glass cap, a method of bonding the metal cap to the substrate by using a method, such as sand blast or etching, to provide a moisture absorbent inside a predetermined groove is used. The method in the related art makes it difficult to process the metal cap due to an expansion of a space inside the encapsulation when a panel becomes large, and may cause a problem in that the glass cap is easily broken by external pressure.
There is a need for developing a new encapsulation technology which is different from the existing encapsulation process due to these difficulties.